Sensing device

ABSTRACT

A sensing device includes a base, a probe structure and a transmitter structure. The base is provided with a first fastener part. The probe structure includes a second fastener part, a probe and a connection area. The transmitter structure includes a transmitter housing and a transmitter disposed inside the transmitter housing, the transmitter housing is provided with a connection hole, the shape of which matches the shape of the probe structure, and when the transmitter structure is mounted to the base, the probe structure is located in the connection hole, and the transmitter is electrically connected to the connection area to receive the signal generated by the probe.

TECHNICAL FIELD

The present invention mainly relates to the field of medicalinstruments, in particular to a sensing device.

BACKGROUND

The pancreas in a normal person can automatically monitor the amount ofglucose in the blood and automatically secrete the required dosage ofinsulin/glucagon. However, for diabetic patients, the function of thepancreas is abnormal, and the pancreas cannot normally secrete requireddosage of insulin. Therefore, diabetes is a metabolic disease caused byabnormal pancreatic function, which is also a lifelong disease. Atpresent, medical technology cannot cure diabetes, and it can onlycontrol the occurrence and development of diabetes and its complicationsby stabilizing blood glucose.

Patients with diabetes need to check their blood glucose beforeinjecting insulin into the body. At present, most of the detectionmethods can continuously detect blood glucose, and send the bloodglucose data to the remote device in real time for the user to view.This detection method is called Continuous Glucose Monitoring (CGM)method. The method requires the sensing device to be attached to thesurface of the patients' skin, and the probe carried by the device isinserted into the subcutaneous tissue fluid for testing.

However, the current sensing device is relatively large and relativelythick, affecting the user's dressing, stretching, exercise and otherdaily activities, which can seriously worsen user experience. Also,detection can be easily interrupted with such a sensing device because abulky device can get bumped or caught easily, which may lead to dataloss and pose a potential safety hazard to the user.

Accordingly, there is a need in the state of the art for a sensingdevice that has a reduced thickness and enhances the user experience.

BRIEF SUMMARY OF THE INVENTION

The embodiment of the invention discloses a sensing device. By specialdesign of its internal structure and simplification of structural units,the thickness dimension of the sensing device is reduced, therebyenhancing the user experience.

The invention discloses a sensing device, comprising: a base, the baseis provided with a first fastener part; a probe structure, the probestructure comprises a second fastener part, a probe and a connectionarea, the second fastener part can be fastened with the first fastenerpart, and the probe is disposed for detecting the analyte parameter inthe body fluid, and the connection area is electrically connected to theprobe, the second fastener part is disposed at the end of the probestructure, and the second fastener part is fastened with the firstfastener part to mount the probe structure to the base; and atransmitter structure, the transmitter structure includes a transmitterhousing and a transmitter disposed inside the transmitter housing, thetransmitter housing is provided with a connection hole, the shape ofwhich matches the shape of the probe structure, and when the transmitterstructure is mounted to the base, the probe structure is located in theconnection hole, and the transmitter is electrically connected to theconnection area to receive the signal generated by the probe.

According to an aspect of the invention, the side wall of the probestructure is provided with a sealing element.

According to an aspect of the invention, the side wall of the probestructure is provided with a rubber sealing ring.

According to an aspect of the invention, the first fastener part isprovided on/in the bottom of the base.

According to an aspect of the invention, the first fastener partincludes a kind of or a combination of at least one slot, or one hole,or one hook or one block.

According to an aspect of the invention, the first fastener partincludes holes or slots, and the second fastener part includes blocksfastened with the holes or the slots of the first fastener part.

According to an aspect of the invention, the first fastener partincludes a plurality of blocks, and the second fastener part includes aplurality of holes or slots fastened with the blocks of the firstfastener part.

According to an aspect of the invention, the first fastener part and thesecond fastener part are both hooks that can be fastened with eachother.

According to an aspect of the invention, the fastening position betweenthe first fastener part and the second fastener part is located in thebottom wall of the base, or located at the inner/outer surface of thebottom of the base.

According to an aspect of the invention, the first fastener partincludes a plurality of blocks or hooks, and the distance between thetop of the first fastener part and the bottom surface of the base is s,s 1.5 mm.

Compared with the prior art, the technical solution of the presentinvention has the following advantages:

In the sensing device disclosed in the present invention, the base isprovided with a first fastener part, and the probe structure includes asecond fastener part fastened with the first fastener part. The probestructure itself disposes a second fastener part, which can be installedto the base without the cooperation of other extra or additionalstructural units, reducing the number of structural components formounting the probe structure and the complexity of the probe structureinstallation process. In addition, the second fastener part is disposedat the end of the probe structure, which lowers the height of the probestructure. At the same time, the fastening position between the firstfastener part and the second fastener part is much closer to the bottomsurface of the base. Furthermore, the transmitter housing is providedwith a connection hole that matches the shape of the probe structure.Only the connection hole is arranged on the transmitter housing, whileno position or space for other structural components is provided on thetransmitter housing, which reduces the thickness of the transmitterstructure and the thickness dimension of the sensing device, therebyenhancing the user experience.

Furthermore, the sensing device of the present invention is providedwith a rubber sealing ring on the side wall of the probe structure. Theprovision of a seal element enhances the degree of sealing of theconnection between the probe structure and the transmitter structure,allowing the sensing device to perform analyte detection in more harshconditions such as wet environments, underwater environments, and thelike. Secondly, setting one, not more, seal rings can further reduce theheight dimension of the probe structure.

Furthermore, the first fastener part are blocks or hooks, and thedistance between the top of the first fastener part and the bottomsurface of the base is s, s≤1.5 mm. The distance between the top of thefirst fastener part and the bottom surface of the base is reduced, andthe fastening position between the first fastener part and the secondfastener part is much closer to the bottom surface of the base, and thetop of the probe is further lowered after the probe structure isinstalled. The lowered probe structure leads to further reduce thicknessof the transmitter structure, ultimately reducing the thicknessdimension of the sensing device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic structural view of a base, a probestructure and a transmitter structure for mounting according to oneembodiment of the present invention;

FIG. 2 illustrates a schematic structural view of a base according toone embodiment of the present invention;

FIG. 3a to FIG. 3c illustrate schematic structural views of a probestructure according to one embodiment of the present invention;

FIG. 4 illustrates a schematic structural view of a probe structuremounted to a base according to one embodiment of the present invention;

FIG. 5a to FIG. 5d illustrate schematic structural views of a firstfastener part and a second fastener part according to embodiments of thepresent invention;

FIG. 6 illustrates a schematic structural view of a transmitterstructure according to one embodiment of the present invention;

FIG. 7a -FIG. 7c illustrate schematic structural views of a sensingdevice in accordance with one embodiment of the present invention.

DETAILED DESCRIPTION

As described above, the prior art sensing device is relatively thick andadhered to the surface of the skin, easily affected by the user'smovement or dressing activities. And the sensing device can get easilybumped or caught, worsening user experience.

It has been found through research that the prior art sensing devicemounts the probe structure to the base by means of an extra oradditional snap ring(s) or hook(s) and the mutual fastening of thepositioning parts on the base. After installation, the top of the probestructure is higher, increasing the thickness of the transmitterstructure, ultimately increasing the thickness of the sensing device.

In order to solve the problem, the present invention provides a sensingdevice. The end of the probe structure itself is provided with a secondfastener part, and the fastening position between the second fastenerpart and the first fastener part is much closer to the bottom surface ofthe base, reducing the thickness of the sensing device, and enhancinguser experience.

Various exemplary embodiments of the present invention will now bedescribed in detail with reference to the drawings. The relativearrangement of the components and the steps, numerical expressions andnumerical values set forth in the embodiments are not to be construed aslimiting the scope of the invention.

In addition, it should be understood that, for ease of description, thedimensions of the various components shown in the figures are notnecessarily drawn in the actual scale relationship, for example, thethickness, the width, the length or the distance of certain units may beexaggerated relative to other structures.

The following description of the exemplary embodiments is merelyillustrative, and is not intended to be in any way limiting theinvention and its application or use. The techniques, methods anddevices that are known to those of ordinary skill in the art may not bediscussed in detail, but such techniques, methods and devices should beconsidered as part of the specification.

It should be noted that similar reference numerals and letters indicatesimilar items in the following figures. Therefore, once an item isdefined or illustrated in a drawing, it will not be discussed further infollowing description of the drawings.

FIG. 1 is a schematic structural view of a mounting position of a base10, a probe structure 100 and a transmitter structure 1000 according toone embodiment of the present invention.

The sensing device of the embodiment of the invention comprises a base10, a probe structure 100 and a transmitter structure 1000. The threestructural units are mounted as a sensing structure in accordance withthe position of the dashed line in FIG. 1. The respective structures andthe positional relationship between the structures will be described indetail below.

The sensing device disclosed by the present invention can be used todetect different body fluid parameter information such as blood glucoseconcentration, drug concentration, hormone information or parameterinformation of other substances. Specifically, in an embodiment of thepresent invention, the sensing device is configured to detectconcentration information of glucose in the tissue fluid in real time,and transmit the obtained information to the remote device in real time.At this point, the sensing device is part of a Continuous GlucoseMonitoring (CGM) system.

FIG. 2 is a schematic structural view of a base 10 according to anembodiment of the present invention.

The base 10 is provided with a first fastener part 110. The firstfastener part 110 is used to mount the probe structure 100.Specifically, in the embodiment of the present invention, the firstfastener part 110 is disposed on the bottom surface of the base 10, asdepicted in FIG. 1. The first fastener part 110 can be disposed on theinner/outer bottom surface of the base 10. Preferably, the firstfastener part 110 is disposed on the inner bottom surface of the base10. The shape of the first fastener part 110 will be described in detailbelow through FIG. 5a to FIG. 5 d.

It should be noted that, in other embodiments of the present invention,the first fastener part 110 may be disposed on the side wall of the base10 or at the same time on the side wall and the bottom surface of thebase 10, and is not specifically limited herein. It suffices that thefirst fastener part 110 and the second fastener part 120 can be fastenedwith each other.

The outer bottom surface of the base 10 (as shown in FIG. 7b ) is alsofixedly provided with medical tape (not shown) to adhere the base 10 tothe skin surface. Positions (not shown) for fixing the transmitterstructure 1000 are also provided on the side wall or bottom of the base10.

FIG. 3a to FIG. 3c are schematic diagrams showing the structure of theprobe structure 100 at different viewing angles according to anembodiment of the present invention.

The probe structure 100 includes a second fastener part 120, a probe 130and a connection area 140.

The second fastener part 120 is configured to fasten with the firstfastener part 110 on the base 10 to mount the probe structure 100.Therefore, in the embodiment of the present invention, the structures ofthe second fastener part 120 and the first fastener part 110 are matchedto each other, which will be described in detail below.

Specifically, in the embodiment of the present invention, the secondfastener part 120, disposed at the bottom end of the probe structure100, forms a part of the probe structure 100. When the second fastenerpart 120 and the first fastener part 110 are fastened with each other,the fastening position is closer to the bottom surface of the base 10.This not only reduces the height h of the probe structure 100, but alsoeliminates the need for extra or additional hooks, snap rings, etc., tomount the probe structure 100 on the base 10, therefore reducing thenumber of the structure components required for mounting the probestructure 100 and the difficulty of designing the probe structure 100and the base 10, and also simplifying the manufacturing process of theprobe structure 100 and the base 10. And after installation, the heightof the top of the probe structure 100 is relatively low, reducing thethickness of the transmitter structure 1000.

In other embodiments of the present invention, a part of the secondfastener part 120 may also be disposed at the top end of the probestructure 100, that is, both ends of the probe structure 120 areprovided with a second fastener part. Obviously, the second fastenerpart 120 at the bottom end thereof can still be fastened with the firstfastener part 110, and the second fastener part 120 at the top end canmatch the shape of other structures, which will be described in detailbelow. Preferably, in the embodiment of the present invention, thesecond fastener parts 120 are disposed at the same end of the probestructure 100.

It should be noted that, in the embodiment of the present invention, thefastening position closer to the bottom surface of the base 10 meansthat the distance between the fastening position and the bottom surfaceof the base 10 is less than or equal to 1.5 mm, or the fasteningposition is located at the inner/outer surface of the bottom of the base10. Or the fastening position is located in the bottom wall of the base10 (the first fastener part as described below is a hole structure).

The embodiment of the present invention does not specifically limit thenumber of the second fastener parts 120, which may be one, two, three,four or more. Specifically, in the embodiment of the present invention,the number of the second fastener parts 120 is four, which makes thelocking firmer.

The probe 130 is used to detect and transmit parameter information ofthe body fluid analyte. The probe 130 includes an upper part and asubcutaneous part. The upper part of the probe 130 is disposed insidethe probe structure 100, while the subcutaneous part is used topenetrate the subcutaneous tissue fluid. An electrode for detectinganalyte parameter information is disposed on the probe 130, and theparameter information is converted into an electrical signal to betransmitted to the transmitter structure 1000.

The connection area 140 is a metal conductive structure and functions asa connection medium for transmitting electrical signals from the probe130 to the transmitter 180. Specifically, in the embodiment of thepresent invention, the connection area 140 is disposed at the top end ofthe probe structure 100.

In other embodiments of the invention, the connection area 140 can alsobe located on the side wall of the probe structure 100, which canfurther reduce the height h of the probe structure 100. At this time,the top end of the probe structure 100 may be provided with a secondfastener part 120 (the second fastener part 120 is disposed at both endsof the probe structure 100) for connecting and engaging with thetransmitter structure 1000, making the connection between differentstructures much stronger.

It should be noted that, in the embodiment of the present invention, theside wall of the probe structure 100 is further provided with a recess15 for placing the sealing element 150 (as depicted in FIG. 1 and FIG.4). The placement of the sealing element 150 within the recess 15provides a better seal between the transmitter structure 1000 and theprobe structure 100, allowing the sensing device to work under moresevere conditions such as humidity, water, and the like. In theembodiment of the present invention, there is only one recess 15, andonly one sealing element 150 is placed, reducing the height h of theprobe structure 100. Specifically, in the embodiment of the presentinvention, the sealing element 150 is a rubber sealing ring.

In other embodiments of the present invention, the probe structure 100may not be provided with the sealing element 150 as long as it can bedesigned without affecting the detection and transmission of the analyteparameter by the probe 130, and is not specifically limited herein.

FIG. 4 depicts a schematic view showing the structure of the probestructure 100 mounted on the base 10 according to an embodiment of thepresent invention.

After the second fastener part 120 and the first fastener part 110 arefastened with each other, the probe structure 100 is mounted to the base10. In the embodiment of the present invention, after the probestructure 100 is mounted to the base 10, the probe structure 100 can beallowed to be slightly shaken, and the probe structure 100 is notnecessarily required to be completely locked on the base 10 as long asthe probe 130's ability to detect the analyte parameter is not affected.

FIG. 5a to FIG. 5d are schematic structural views of the first fastenerpart and the second fastener part before being fastened in differentembodiments of the present invention.

FIG. 5a shows the structure of the first fastener part 110 according tothe embodiment of the present invention, and a plurality of hookscompose the first fastener part 110 i. In order to match the hooks ofthe first fastener part 110, the second fastener part 120 also includeshooks, which can be fastened with the first fastener part 110.

In the embodiment of the present invention, the hooks protrudes from theinner bottom surface of the base 10, and the distance between the topsurface of the first fastener part 110 and the inner bottom surface ofthe base 10 (the height dimension of the hook) is s, s≤1.5 mm.Specifically, in the embodiment of the present invention, s=0.8 mm. Inanother embodiment of the invention, s=1 mm.

FIG. 5b shows the structure of the first fastener part 210 according toanother embodiment of the present invention, and multiple holes composethe first fastener part 210. At this time, the second fastener part 220includes blocks, being matched with the holes structure of the firstfastener part 210. The inner wall of the holes and the outer wall of theblocks are respectively provided with matching bumps to facilitatemutual fastening. At this time, the fastening positions between thefirst fastener part 210 and the second fastener part 220 are locatedinside the bottom wall of the base 20.

It should be noted that, in other embodiments of the present invention,after the fastening of the first fastener part 210 and the secondfastener part 220, the second fastener part 220 can also pass throughthe hole 210 to protrude out of the base 20. The outer part of thesecond fastener part 220 from the base 20 is not limited as long as itdoes not affect the detection of the probe or the wearing of the sensingdevice.

FIG. 5c shows the structure of the first fastener part 310 according tostill another embodiment of the present invention. A plurality of hookscompose the first fastener part 310. The second fastener part 320 alsoincludes blocks, being matched with the slots structure of the firstfastener part 310. Similarly, the fastening positions between the firstfastener part 310 and the second fastener part 320 are located insidethe bottom wall of the base 30.

FIG. 5d shows the structure of the first fastener part 410 according tostill another embodiment of the present invention, and the firstfastener part 410 includes blocks. The second fastener part 420 alsocomprises blocks.

Similarly, in the embodiment of the present invention, the distancebetween the top of the blocks of the first fastener part 410 and theinner bottom surface of the base 40 (the height dimension of the blocks)is s, s≤1.5 mm. Specifically, in the embodiment of the presentinvention, s=0.5 mm. In still another embodiment of the invention, s=0.3mm.

Obviously, the structure of the first fastener part and the secondfastener part can be reversed as described above. For example, thesecond fastener part may be holes or slots, and the first fastener partincludes blocks corresponding to the second fastener part. Or the firstfastener part is a plurality of combinations of hooks, holes, slots andblocks. It is obvious that the second fastener part is also a pluralityof combinations of the above structures, so as to be fastened with thefirst fastener part. There is no specific restriction herein, as long asit can satisfy the purpose of matching each other.

According to another embodiment, the number of the hook, the hole, theslot or the block is only one. That is the first fastener part is ahook, a hole, a slot or a block, and the number of the second fastenerpart is also one, corresponding to the first fastener part, which canalso fasten the first fastener part and the second fastener part. And itis not limited herein.

Similarly, in another embodiment of the present invention, the firstfastener part may also protrude from the outer bottom surface of thebase, that is, the first fastener part protrudes from the outer surfaceof the base toward the skin surface. After the second fastener part andthe first fastener part are matched to each other according to the abovestructure and size, they both can still be fastened with each otherwithout affecting the operation of the sensing device. At this time,when the first fastener part is a block or a hook, the distance s isbetween the top of the first fastener part and the outer bottom surfaceof the base, s≤1.5 mm.

It should be noted that since the probe structure itself is providedwith the second fastener part, it can be mounted on the base withoutusing other extra or additional structural units. Therefore, even if thefirst fastener part is a block or a hook protruding from the bottomsurface of the base, the height dimension s of the first fastener partis still relatively small, and the fastening positions between the firstfastener part and the second fastener part are much closer to the bottomof the base. After the probe structure is installed, the top of theprobe structure is lowered, further reducing the thickness of the entiresensing device.

FIG. 6 is a schematic structural diagram of a transmitter structure 1000according to an embodiment of the present invention. FIG. 7a to FIG. 7care schematic structural views of the base 10, the probe structure 100,and the transmitter structure 1000 installed at different viewing anglesaccording to an embodiment of the present invention.

The transmitter structure 1000 includes a transmitter 180 and atransmitter housing 160.

The transmitter 180 is disposed inside the transmitter housing 160. Thetransmitter 180 is coupled to connection area 140 to receive signalsgenerated by probe 130.

The transmitter housing 160 is provided with a connection hole 170 thatmatches the shape of the probe structure 100. When the transmitterstructure 1000 is coupled to the probe structure 100, the probestructure 100 is located within the connection hole 170. Here, matchingthe shape of the probe structure 100 means that the shape of theconnection hole 170 will be designed solely according to the probestructure 100 without considering the shape of other structure units. Asdescribed above, in the embodiment of the present invention, the heighth of the probe structure 100 is reduced, thus ultimately reducing thethickness w of the transmitter structure 1000 (as shown in FIG. 7c ).

Obviously, as described above, when the top end of the probe structure100 is also provided with the second fastener part 120, the connectinghole 170 is also provided with a fastening structure matching the topend of the second fastener part 120. This will result in strongerconnection between the transmitter structure 1000 and the probestructure 100.

In the structure of one kind of sensing device, not only a positioningpart is provided on the base to prevent the probe structure aftermounting from rotating, but also a fastener part is disposed on thebase, and the probe structure is not provided with other fastener partsmatched with the base fastener part. Therefore, the probe structureneeds to be locked by using other additional hooks, snap rings, etc. Thecombination of the hook or the snap ring with the positioning partattaches the probe structure to the base, which increases the number ofstructural units, the number of steps of the fastening procedure and thedifficulty of structure design. Moreover, due to the presence of thepositioning part, the height of the fastener part on the base isrelatively large, and the structure is also more complicated. At thesame time, an additional snap ring or hook is placed at a fartherposition from the bottom surface of the base, and the fastening positionis also farther from the bottom surface of the base. So that thestructures/positions and spaces for placing the higher fastener part(snap ring or hook) or the higher fastening position have to be designedin/on the transmitter housing, thus increasing the thickness of thetransmitter structure and worsening user experience.

In the sensing device of the embodiment of the present invention, theprobe structure itself is provided with a second fastener part, and thesecond fastener part is disposed at the end of the probe structure, sothat the final fastening position is closer to the bottom surface of thebase, thereby reducing the height of the probe structure. Secondly, theheight of the first fastener part is small, which further makes thefastening position closer to the bottom surface of the base. After theprobe structure is installed, the height of the top of the probestructure is lowered. The transmitter housing does not requireadditional space and structure/position to match the first fastener partor fastening position, further reducing the thickness of thetransmitter. In the embodiment of the present invention, the fewerfastening structural units in the sensing device, the smaller height ofthe probe structure, and the smaller thickness of the transmitterstructure reduce the overall thickness dimension w of the sensing devicein this present invention by more than 30%, compared with the prior art.

When the sensing device of the embodiment of the present invention isused for Continuous Glucose Monitoring (CGM) system, the transmittertransmits the glucose parameter information obtained in real time to aremote device (such as a receiver, a handset, a PDM, a mobile terminal,an internet terminal, etc.). After the thinner sensing device isattached to the surface of the user's skin, the degree of interferenceof the user's dressing action on the sensing device is reduced.Especially when the clothes are thick, the user will have a morecomfortable experience using a thinner sensing device. At the same time,the thinner-sized sensing device further reduces the degree of influenceon the user's stretching movements and other daily activities resultingin a superior user experience.

In summary, the embodiment of the invention discloses a sensing device.By designing each structure, the thickness dimension of the sensingdevice is finally reduced, reducing the volume of the sensing device andenhancing user experience.

While the invention has been described in detail with reference to thespecific embodiments of the present invention, it should be understoodthat it will be appreciated by those skilled in the art that the aboveembodiments may be modified without departing from the scope and spiritof the invention. The scope of the invention is defined by the appendedclaims.

1. A sensing device, comprising: a base, wherein the base is providedwith a first fastener part; a probe structure, wherein the probestructure comprises a second fastener part, a probe and a connectionarea, the second fastener part is able to be fastened with the firstfastener part, and the probe is disposed for detecting a analyteparameter in a body fluid, and the connection area is electricallyconnected to the probe, the second fastener part is disposed at an endof the probe structure, and the second fastener part is fastened withthe first fastener part to mount the probe structure to the base; and atransmitter structure, wherein the transmitter structure includes atransmitter housing and a transmitter disposed inside the transmitterhousing, the transmitter housing is provided with a connection hole, ashape of the connection hole matches a shape of the probe structure, andwhen the transmitter structure is mounted to the base, the probestructure is located in the connection hole, and the transmitter iselectrically connected to the connection area to receive a signalgenerated by the probe.
 2. The sensing device of claim 1, wherein a sidewall of the probe structure is provided with a sealing element.
 3. Thesensing device of claim 2, wherein the side wall of the probe structureis provided with a rubber sealing ring.
 4. The sensing device of claim1, wherein the first fastener part is provided on/in a bottom of thebase.
 5. The sensing device of claim 4, wherein the first fastener partincludes one of or a combination of at least one slot, or one hole, orone hook or one block.
 6. The sensing device of claim 5, wherein thefirst fastener part includes holes or slots, and the second fastenerpart includes blocks fastened with the holes or the slots of the firstfastener part.
 7. The sensing device of claim 5, wherein the firstfastener part includes a plurality of blocks, and the second fastenerpart includes a plurality of holes or slots fastened with the blocks ofthe first fastener part.
 8. The sensing device of claim 5, wherein thefirst fastener part and the second fastener part are both hooks that canbe fastened with each other.
 9. The sensing device of claim 5, wherein afastening position between the first fastener part and the secondfastener part is located in a bottom wall of the base, or located at ainner/outer surface of the bottom of the base.
 10. The sensing device ofclaim 5, wherein the first fastener part includes a plurality of blocksor hooks, and a distance between a top of the first fastener part and abottom surface of the base is s, and s≤1.5 mm.